Patients suffering from mandible tumors often require a reconstructive surgery to repair the defects caused by large tumors. The particular type of reconstructive surgery studied in this paper is called free fibular flap reconstruction, which uses fibular segments to replace removed sections of the mandible and a titanium plate to provide strength. In order to decrease the dependence on design experience, decrease surgery time, and enhance the participation of surgeons in the design process, Rapid Prototyping (RP) biomedical models were employed to enable good visualization of the original and reconstructed geometry and for use as forming guides for the customized titanium plates. This study reports on one male and one female patients who underwent mandibular reconstruction. In one case, the operation time was reduced 2 hours and the other one was reduced 1.8 hours. The customized titanium plate shapes conformed to the patients’ mandible anatomy and were thick enough to provide the strength and stiffness needed to fix the mandible until the bone grafts and soft tissues heal.